1. Field of the Invention
With regard to the classification of the art, this invention is believed to be found in the general class entitled: "Road Structure, Process and Apparatus", and more particularly to the subclasses pertaining to "Tamper Apparatus".
2. Description of the Prior Art
Plate compactors or Tampers are known in the art. Reversible plate compactors are the subject of several known U.S. patents. These known patents are U.S. Pat. Nos. 3,001,458 issued to Croucher on Sep. 26, 1961; 3,603,224 issued to Dresher on Sep. 7, 1971; 3,832,080 issued to Stoecker on Aug. 27, 1974; 3,972,637 issued to Sutherland on Aug. 3, 1976; and 5,149,225 issued to Artzberger on Sep. 22, 1992.
U.S. Pat. Nos. 3,001,458 and 3,832,080 employ the principles of adjusting the phase angle relationship of a pair of counter-rotating eccentrics. This type of apparatus employs complex adjusting means which has a relatively short service life as a result of the stress and the environment in which operates.
U.S. Pat. No. 3,972,637 mounts the tamper plate on a vertical axis. This mounting allows the eccentric drive to be rotated about a vertical axis with respect to the compactor plate. Space considerations at the work site have made this reversing feature unusable. In many cases, the compactor must be reversed while the operator is close to a corner.
U.S. Pat. No. 3,603,224 discloses a plate compactor having a pair of eccentrics. The direction of movement is determined by the direction of rotation of the eccentrics. This arrangement requires a reversible transmission which has been found to be very expensive while lowering the service life of the compactor.
U.S. Pat. No. 5,149,225 discloses a pair of eccentrically weighted shafts fixed to a compactor plate. Each of the eccentrically weighted shafts is independently rotated by a transmission mechanism. This arrangement requires that the eccentrically weighted shafts be rotated in opposite directions for providing the desired directional movement.
All of the known reversible plate compactors include somewhat sophisticated drives. These drives add complexity to the apparatus as well as cost. The complexity of some of the arrangements require that in some cases elaborate repair parts be maintained at the work site. It has been found that an apparatus which provides reversing capability at a reasonable cost is needed. This desired plate compactor should include a simplicity of construction, operation, and maintenance.
The present invention solves the indentified limitations of the prior art. The present invention also includes a plate compactor whose reversing capabilities are irrespective of drive rotation.